Multipath charger and charging method thereof

ABSTRACT

A multipath charger includes a first charging path, a second charging path, and a management module. A supply voltage is coupled through the first charging path and the second charging path to a battery. The management module provides the supply voltage and detects the operating state of the battery. The management module selectively enables the first charging path, the second charging path, or both according to the operating state of the battery, so as to charge the battery through the enabled charging path.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/763,587, filed Jul. 27, 2015, entitled “MULTIPATH CHARGER ANDCHARGING METHOD THEREOF”, which is a national stage filing under 35U.S.C. § 371 of International Patent Application Ser. No.PCT/CN2014/094832, filed Dec. 24, 2014, entitled “MULTIPATH CHARGER ANDCHARGING METHOD THEREOF”, which claims priority to U.S. ProvisionalApplication Ser. No. 61/920,848, filed Dec. 26, 2013, entitled “MULTIPLECHARGING PATHS”. The entire contents of these applications areincorporated herein by reference in their entirety.

TECHNICAL FIELD

The disclosure generally relates to a multipath charger, and moreparticularly, to a multipath charger to charge a battery with highefficiency.

BACKGROUND

As technology advances, mobile electronic devices are becoming more andmore popular. For example, smartphones, tablet computers, and notebookcomputers play an important role in the lives of modern people. Mobileelectronic devices are usually supplied with power by their batteries.Nowadays, people prefer batteries with large capacity, but it has becomea critical challenge to charge large-capacity batteries in a short time.Generally speaking, a conventional charger uses only one charging pathto charge a battery, and such a design has disadvantages, such as a longcharging time, thermal effects, and insufficient charging capabilities.As a result, there is a need to design a novel charger to overcome theproblems of the prior art.

SUMMARY

In one exemplary embodiment, the disclosure is directed to a multipathcharger including a first charging path, a second charging path, and amanagement module. A supply voltage is coupled through the firstcharging path and the second charging path to a battery. The managementmodule provides the supply voltage and detects an operating state of thebattery. The management module selectively enables the first chargingpath, the second charging path, or both according to the operating stateof the battery, so as to charge the battery through the enabled chargingpath.

In some embodiments, the second charging path is completely separatefrom the first charging path.

In some embodiments, the management module is further coupled to one ormore adapters so as to obtain electric power and generate the supplyvoltage.

In some embodiments, the adapters include an AC (Alternating Current)adapter and/or a USB (Universal Serial Bus) adapter.

In some embodiments, the first charging path is implemented with a maincharging circuit, and the second charging path is implemented with anauxiliary charging circuit.

In some embodiments, the main charging circuit is a switching chargingcircuit.

In some embodiments, the switching charging circuit includes a firstPMOS transistor (P-type Metal Oxide Semiconductor Field EffectTransistor), an NMOS transistor (N-type Metal Oxide Semiconductor FieldEffect Transistor), and an inductor. The first PMOS transistor has agate controlled by the management module, a source coupled to the supplyvoltage, and a drain coupled to an inner node. The NMOS transistor has agate controlled by the management module, a source coupled to a groundvoltage, and a drain coupled to the inner node. The inner node iscoupled through the inductor to the battery.

In some embodiments, the auxiliary charging circuit is a linear chargingcircuit or a wireless charging circuit.

In some embodiments, the linear charging circuit includes a second PMOStransistor (P-type Metal Oxide Semiconductor Field Effect Transistor).The second PMOS transistor has a gate controlled by the managementmodule, a source coupled to the supply voltage, and a drain coupled tothe battery.

In some embodiments, the management module further detects connectionstates and capabilities of the adapters.

In some embodiments, when the AC adapter and the USB adapter are bothcoupled to the management module, the management module enables both themain charging circuit and the auxiliary charging circuit.

In some embodiments, when only the AC adapter is coupled to themanagement module and the AC adapter has a capability of supplying arelatively large power current, the management module enables both themain charging circuit and the auxiliary charging circuit.

In some embodiments, when only the AC adapter is coupled to themanagement module and the AC adapter has a capability of supplying arelatively small power current, the management module enables the maincharging circuit and disables the auxiliary charging circuit.

In some embodiments, when only the USB adapter is coupled to themanagement module, the management module enables the main chargingcircuit and disables the auxiliary charging circuit.

In some embodiments, when the AC adapter and the USB adapter are bothdecoupled from the management module, the management module disablesboth the main charging circuit and the auxiliary charging circuit.

In some embodiments, the operating state of the battery includes abattery voltage, a battery temperature, and a battery capacity.

In some embodiments, when the battery temperature is higher than atemperature threshold, the management module reduces currents on thefirst charging path and/or the second charging path.

In some embodiments, when the battery temperature is higher than atemperature threshold, the management module disables one or both thefirst charging path and the second charging path.

In another exemplary embodiment, the disclosure is directed to a methodfor charging a battery, including the steps of: providing a firstcharging path and a second charging path, wherein a supply voltage iscoupled through the first charging path and the second charging path tothe battery; detecting an operating state of the battery; selectivelyenabling the first charging path, the second charging path, or bothaccording to the operating state of the battery; and charging thebattery through the enabled charging path.

BRIEF DESCRIPTION OF DRAWINGS

The invention can be more fully understood by reading the subsequentdetailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1 is a diagram of a multipath charger according to an embodiment ofthe invention;

FIG. 2 is a diagram of a multipath charger according to an embodiment ofthe invention;

FIG. 3 is a diagram of a multipath charger coupled to a battery circuitaccording to an embodiment of the invention;

FIG. 4 is a flowchart of an enable-selection process of a managementmodule according to an embodiment of the invention;

FIG. 5 is a diagram of a charging state of a battery according to anembodiment of the invention; and

FIG. 6 is a flowchart of method for charging a battery according to anembodiment of the invention.

DETAILED DESCRIPTION

In order to illustrate the purposes, features and advantages of theinvention, the embodiments and figures of the invention will bedescribed in detail as follows.

FIG. 1 is a diagram of a multipath charger 100 according to anembodiment of the invention. The multipath charger 100 may be used in amobile electronic device, such as a smartphone, a tablet computer, amedia player, a music player, or a notebook computer. As shown in FIG.1, the multipath charger 100 at least includes a first charging path110, a second charging path 120, and a management module 130. Themultipath charger 100 may be an independent circuit chip designed in themobile electronic device. The mobile electronic device includes abattery 140. The battery 140 supplies electric power to the mobileelectronic device. During a charging process, the battery 140 is chargedthrough the multipath charger 100 by one or more external adapters 150,which are accessories of the mobile electronic device. The managementmodule 130 may be coupled to one or more adapters 150, so as to obtainelectric power therefrom and generate a supply voltage VDDM. When thebattery 140 is charged, the supply voltage VDDM may be coupled throughthe first charging path 110 and/or the second charging path 120 to thebattery 140. Preferably, the second charging path 120 is completelyseparate from the first charging path 110. The management module 130further detects the operating state of the battery 140 and thereforeoptimizes the efficiency of the charging process. More particularly,during the charging process, the management module 130 selectivelyenables the first charging path 110, the second charging path 120, orboth according to the operating state of the battery 140, so as tocharge the battery 140 through the enabled charging path. In otherwords, the supply voltage VDDM may be coupled through the first chargingpath 110, the second charging path 120, or both to the battery 140. Inthe invention, the multipath charger 100 can use more than one chargingpath to charge the battery 140, and which has the advantage ofincreasing the charging efficiency, reducing the thermal effect, andshortening the total charging time, in comparison with the prior art.The detailed structure and operation of the multipath charger 100 willbe described in the following embodiments. It should be understood thatthese embodiments are just exemplary, rather than restrict limitationsof the invention.

FIG. 2 is a diagram of a multipath charger 200 according to anembodiment of the invention. In the embodiment of FIG. 2, the multipathcharger 200 at least includes a first charging path 210, a secondcharging path 220, and a management module 230. Similarly, the multipathcharger 200 may be used in a mobile electronic device, and the mobileelectronic device may include a battery 240. When the battery 240 ischarged, the multipath charger 200 may be coupled to one or moreadapters, so as to obtain electric power therefrom and generate a supplyvoltage VDDM. For example, the aforementioned adapters may include an AC(Alternating Current) adapter 251, a USB (Universal Serial Bus) adapter252, or both. The mobile electronic device with the multipath charger200 may have at least two separate sockets for connection with the ACadapter 251 and the USB adapter 252. The AC adapter 251 may have a firstterminal coupled to a fixed AC power source (not shown), and a secondterminal coupled to the management module 230. The USB adapter 252 mayhave a USB terminal coupled to a desktop computer (not shown), and aMicro-USB terminal coupled to the management module 230.

In the embodiment of FIG. 2, the first charging path 210 is implementedwith a main charging circuit, and the second charging path 220 isimplemented with an auxiliary charging circuit. The main chargingcircuit has a relatively strong ability to charge the battery 240, andthe auxiliary charging circuit has a relatively weak ability to chargethe battery 240. For example, the main charging circuit may be aswitching charging circuit, and the auxiliary charging circuit may be alinear charging circuit. Alternatively, the auxiliary charging circuitmay be replaced with a wireless charging circuit (not shown).

As shown in FIG. 2, the main charging circuit (i.e., the switchingcharging circuit) includes a first PMOS transistor (P-type Metal OxideSemiconductor Field Effect Transistor) MP1, an NMOS transistor (N-typeMetal Oxide Semiconductor Field Effect Transistor) MN, and an inductorL1. The first PMOS transistor MP1 has a gate controlled by themanagement module 230, a source coupled to the supply voltage VDDM, anda drain coupled to an inner node NN. The NMOS transistor MN has a gatecontrolled by the management module 230, a source coupled to a groundvoltage VSS, and a drain coupled to the inner node NN. The inner node NNis coupled through the inductor L1 to the battery 240. A DC-to-DC(Direct Current to Direct Current) converter is formed by the first PMOStransistor MP1 and the NMOS transistor MN. The management module 230 mayuse a first driver 271 (optional element) to control the gate of thefirst PMOS transistor MP1 and the gate of the NMOS transistor MN. Whenthe main charging circuit is enabled, the management module 230periodically turns on and off the first PMOS transistor MP1 and the NMOStransistor MN, and therefore the average output voltage at the innernode NN is lower than the supply voltage VDDM. The inductor L1 caneliminate the high-frequency components of the output voltage at theinner node NN, and it serves as a low-pass filter. According to theenergy conservation law, since the average output voltage at the innernode NN is lower than the supply voltage VDDM, the average outputcurrent through the main charging circuit to the battery 240 should belarger than the supply current from the supply voltage VDDM. As aresult, the main charging circuit has a relatively strong ability tocharge the battery 240.

The auxiliary charging circuit (i.e., the linear charging path) includesa second PMOS transistor (P-type Metal Oxide Semiconductor Field EffectTransistor) MP2. The second PMOS transistor MP2 has a gate controlled bythe management module 230, a source coupled to the supply voltage VDDM,and a drain coupled to the battery 240. The management module 230 mayuse a second driver 272 (optional element) to control the gate of thesecond PMOS transistor MP2. When the auxiliary charging circuit isenabled, the management module 230 turns on the second PMOS transistorMP2. Since the second PMOS transistor MP2 has a turned-on resistancewhich results in an IR drop, the auxiliary charging circuit has arelatively weak ability to charge the battery 240.

As mentioned above, the management module 230 selectively enables themain charging circuit, the auxiliary charging circuit, or both accordingto the operating state of the battery 240. In alternative embodiments,the management module 230 further detects the connection states and thecapabilities of the adapters, and performs the above enable-selectionprocess accordingly. More particularly, the enable-selection processrelative to the adapters are described in Table I as follows.

TABLE I Relationship Between Connection of Adapters and Selection ofCharging Paths Main Charging Auxiliary Charging Case AC Adapter USBAdapter Circuit Circuit 1 Connected Connected Enabled Enabled 2/3Connected Disconnected Enabled Enabled/Disabled 4 Disconnected ConnectedEnabled Disabled 5 Disconnected Disconnected Disabled Disabled

Please refer to Table I to understand the five different enableselection cases. In the first case, when it is detected that the ACadapter 251 and the USB adapter 252 are both coupled to the managementmodule 230, the management module 230 enables both the main chargingcircuit and the auxiliary charging circuit, such that the battery 240 ischarged by the supply voltage VDDM through both the main chargingcircuit and the auxiliary charging circuit. Under the circumstance, theAC adapter 251 and the USB adapter 252 are considered as a combinedsuper adapter, and the multipath charger 200 can charge the battery 240in the shortest time by using both charging paths.

In the second case, when it is detected that only the AC adapter 251 iscoupled to the management module 230 and the AC adapter 251 has thecapability of supplying a relatively large power current (i.e., a strongAC power source), the management module 230 enables both the maincharging circuit and the auxiliary charging circuit, such that thebattery 240 is charged by the supply voltage VDDM through both the maincharging circuit and the auxiliary charging circuit. The second case issimilar to the first case. Because the AC adapter 251 supplies arelatively large power current, it can be used as a super adapter, andthe multipath charger 200 can charge the battery 240 by using bothcharging paths.

In the third case, when it is detected that only the AC adapter 251 iscoupled to the management module 230 and the AC adapter 251 has thecapability of supplying a relatively small power current (i.e., a weakAC power source), the management module 230 enables the main chargingcircuit and disables the auxiliary charging circuit, such that thebattery 240 is charged by the supply voltage VDDM through only the maincharging circuit. Under the circumstance, the AC adapter 251 merelysupplies a relatively small power current, and there is no need to useboth the main charging circuit and the auxiliary charging circuit. Sincethe main charging circuit has higher charging efficiency, the managementmodule 230 enables only the main charging circuit to charge the battery240.

In the fourth case, when it is detected that only the USB adapter 252 iscoupled to the management module 230, the management module 230 enablesthe main charging circuit and disables the auxiliary charging circuit,such that the battery 240 is charged by the supply voltage VDDM throughonly the main charging circuit. The fourth case is similar to the thirdcase. The USB adapter 252 merely supplies a relatively small powercurrent, and there is no need to use both the main charging circuit andthe auxiliary charging circuit. Since the main charging circuit hashigher charging efficiency, the management module 230 enables only themain charging circuit to charge the battery 240.

In the fifth case, when it is detected that the AC adapter 251 and theUSB adapter 252 are both decoupled from the management module 230, themanagement module 230 disables both the main charging circuit and theauxiliary charging circuit, such that no charging path is formed betweenthe supply voltage VDDM and the battery 240. Under the circumstance, thecharging process of the battery 240 is completely stopped.

It should be understand that the figuration of the multipath charger 200of FIG. 2 is just exemplary, and other figurations with similarfunctions are acceptable in the invention. In some embodiments, themultipath charger 200 includes more than two charging paths and iscoupled to more than two adapters (not shown). The multipath charger 200may select and enable one or more charging paths according to theconnection states and capabilities of the adapters, and according to theoperating state of the battery 240. In alternative embodiments, themultipath charger 200 may include two or more main charging circuitsand/or two or more auxiliary charging circuits, and the multipathcharger 200 may be coupled to two or more AC adapters and/or two or moreUSB adapters.

FIG. 3 is a diagram of a multipath charger 300 coupled to a batterycircuit according to an embodiment of the invention. Similarly, themultipath charger 300 selectively enables its two or more charging paths(not shown) according to the operating state of a battery 340. In theembodiment of FIG. 3, the operating state of the battery 340 includes abattery voltage, a battery temperature, and a battery capacity. Theoperating state of the battery 340 is detected by the multipath charger300 from the battery circuit. In the battery circuit, the battery 340 isintegrated with a NTC (Negative Temperature Coefficient) resistor RT anda battery capacity resistor RC. The battery 340 is coupled to themultipath charger 300 at a first node N1. The NTC resistor RT is coupledto the multipath charger 300 at a second node N2. The battery capacityresistor RC is coupled to the multipath charger 300 at a third node N3.By detecting signals from the first node N1, the second node N2, and thethird node N3, the management module (not shown) of the multipathcharger 300 can obtain details about the operating state of the battery340, such as the battery voltage, the battery temperature, and thebattery capacity. The operating state of the battery 340 may be used todetermine and optimize the above enable selection of charging paths. Theother resistors R1, R2, R3 and the other nodes N4, N5, N6 can providecurrent paths, and charging currents from the multipath charger 300 canflow to the battery 340 through such current paths.

FIG. 4 is a flowchart of an enable-selection process of a managementmodule according to an embodiment of the invention. In the embodiment ofFIG. 4, the enable-selection process performed by the management moduleof a multipath charger is described in detail as follows. In step S410,the management module checks the capacity of a battery. Next, in stepS420, the management module checks whether any adapter is coupled to themultipath charger (i.e., it checks the connection state of the adapter).If so, the management module may further check the capability of theadapter coupled thereto. For example, the adapter's ability to supply apower current may be checked. In step S430, the management module checksthe temperature and the voltage of the battery. Then, in step S440, themanagement module selects and enables one or more of charging pathsaccording to the connection state of the adapter, the capability of theadapter, the battery capacity, the battery voltage, and/or the batterytemperature. In step S450, the management module charges the batterythrough the enabled charging path. In step S460, during the chargeprocess, the management module checks whether the battery temperature ishigher than a temperature threshold. If so, in step S470, the managementmodule may reduce the currents on the enabled charging path, and/or maydisable one or more of the charging paths, such that the batterytemperature may be decreased. If no, in step S480, the charge processmay be maintained, and the management module may continuously monitorthe connection state of the adapter, the capability of the adapter, thebattery capacity, the battery voltage, and/or the battery temperature.When the operating state of the battery is changed and/or the connectionstate and the capability of the adapter is changed, the managementmodule may reselect the charging paths accordingly; that is, theenable-selection process may go back to step S440 again.

FIG. 5 is a diagram of a charging state of a battery according to anembodiment of the invention. The horizontal axis represents a voltagedifference of the battery (VBAT), and the vertical axis represents acurrent through the battery (BAT). In the embodiment of FIG. 5, it isassumed that a capacity of the battery is equal to 2500 mAh, but theinvention is not limited thereto. As shown in FIG. 5, when the batteryvoltage is lower than a first voltage threshold (e.g., 3.4V), themanagement module selects a pre-CC (Pre-Constant Current) mode to chargethe battery. In the pre-CC mode, the current through the battery isrelatively small (e.g., 250 mA). Once the battery voltage is charged upand higher than the first voltage threshold (e.g., 3.4V), the managementmodule selects a CC (pre-Constant Current) mode to charge the battery.In the CC mode, the current through the battery is relatively large(e.g., 2500 mAh, i.e., 10 times the current in the pre-CC mode). Then,when the battery voltage reaches a second voltage threshold (e.g.,4.3V), the management module selects a CV (Constant Voltage) mode tocharge the battery. In the CV mode, the current through the batterybecomes very small, and the charging process is gradually stopped at afull-charge battery voltage (e.g., 4.35V). The aforementionedenable-selection process may be performed by the management module ofthe multipath charger while the battery is being operated in the CCmode. On the other hand, in the pre-CC mode or the CV mode, themanagement module of the multipath charger usually enables only onepredetermined charging path (e.g., a main charging circuit) to chargethe battery.

FIG. 6 is a flowchart of method for charging a battery according to anembodiment of the invention. In step S610, a first charging path and asecond charging path are provided, and a supply voltage is coupledthrough the first charging path and the second charging path to abattery. In step S620, the operating state of the battery is detected.In step S630, the first charging path, the second charging path, or bothare selectively enabled according to the operating state of the battery.In step S640, the battery is charged through the enabled charging path.It should be understood that the above steps are not required to beperformed sequentially, and any one or more features of the embodimentsof FIGS. 1 to 5 may be applied to the method of FIG. 6.

The invention provides a multipath charger and a method for charging abattery. The multipath charger can selectively enable one or morecharging paths, so as to optimize the efficiency of the charging processof the battery. Since the battery may be charged through more than onecharging paths, the proposed multipath charger can provide a strongercharging capability than a conventional design, and such a design may beused to shorten the total charging time and reduce the thermal effect(because the thermal effect is distributed to more charging paths).Furthermore, the cost of the wires and adapters may be decreased becausethey are merely operated at a relatively low temperature and cheapermaterials may be adopted.

The above values of voltages, currents, and resistances are justexemplary, rather than limitations of the invention. One of ordinaryskill may adjust these settings according to different requirements. Itis understood that the multipath charger and the charging method thereofare not limited to the configurations and flowcharts of FIGS. 1 to 6.The invention may merely include any one or more features of any one ormore embodiments of FIGS. 1 to 6. In other words, not all of thefeatures shown in the figures should be implemented in the charge pumpand the operating method of the invention.

Use of ordinal terms such as “first”, “second”, “third”, etc., in theclaims to modify a claim element does not by itself connote anypriority, precedence, or order of one claim element over another or thetemporal order in which acts of a method are performed, but are usedmerely as labels to distinguish one claim element having a certain namefrom another element having the same name (but for use of the ordinalterm) to distinguish the claim elements.

While the invention has been described by way of example and in terms ofthe preferred embodiments, it is to be understood that the invention isnot limited to the disclosed embodiments. On the contrary, it isintended to cover various modifications and similar arrangements (aswould be apparent to those skilled in the art). Therefore, the scope ofthe appended claims should be accorded the broadest interpretation so asto encompass all such modifications and similar arrangements.

The invention claimed is:
 1. A multipath charger for charging a battery,comprising: an adapter, wherein the adapter receives power through awired connection; a first charging path; a second charging path, whereina supply voltage is coupled through the first charging path and thesecond charging path to the battery; and a management module, providingthe supply voltage, and detecting an operating state of the battery,wherein the management module is configured to selectively enable one ofthree charging modes, whereby: in a first charging mode, the managementmodule enables the first charging path, in a second charging mode, themanagement module enables the second charging path, and in a thirdcharging mode, the management module simultaneously enables both thefirst charging path and the second charging path, wherein the enabledcharging mode is determined according to the operating state of thebattery, so as to charge the battery through the enabled charging pathor paths, wherein the first charging path comprises a switching chargingcircuit and the second charging path comprises a linear chargingcircuit, and wherein both the first charging path and the secondcharging path receive power from the adapter.
 2. The multipath chargeras claimed in claim 1, wherein the second charging path is completelyseparate from the first charging path.
 3. The multipath charger asclaimed in claim 1, wherein the first charging path is implemented witha main charging circuit, and the second charging path is implementedwith an auxiliary charging circuit.
 4. The multipath charger as claimedin claim 1, wherein the switching charging circuit comprises: a PMOStransistor (P-type Metal Oxide Semiconductor Field Effect Transistor),wherein the PMOS transistor has a gate controlled by the managementmodule, a source coupled to the supply voltage, and a drain coupled toan inner node; an NMOS transistor (N-type Metal Oxide SemiconductorField Effect Transistor), wherein the NMOS transistor has a gatecontrolled by the management module, a source coupled to a groundvoltage, and a drain coupled to the inner node; and an inductor, whereinthe inner node is coupled through the inductor to the battery.
 5. Themultipath charger as claimed in claim 1, wherein the linear chargingcircuit comprises; a PMOS transistor (P-type Metal Oxide SemiconductorField Effect Transistor), wherein the PMOS transistor has a gatecontrolled by the management module, a source coupled to the supplyvoltage, and a drain coupled to the battery.
 6. The multipath charger asclaimed in claim 1, wherein the operating state of the battery comprisesat least one of a battery voltage, a battery temperature, and a batterycapacity.
 7. The multipath charger as claimed in claim 6, wherein whenthe battery temperature is higher than a temperature threshold, themanagement module reduces a current through the first charging pathand/or the second charging path.
 8. The multipath charger as claimed inclaim 6, wherein when the battery temperature is higher than atemperature threshold, the management module disables one or both of thefirst charging path and the second charging path.